Many home owners want a smart home but do not want to change the switches or break walls. The answer is hidden modules: small units fitted behind the existing switch or in the ceiling box, so the home keeps its look and gains control from the phone and scenes. This guide explains how they work and which module to choose, all available in the Fu-Mech online store.
Key points
- The module fits behind the existing switch, which still works by hand.
- It needs live and neutral (N & L) in the box.
- Modules for lighting, dimming, curtains, garage doors and linking systems.
- -Z models need a Zigbee gateway such as NEXHUB-NH.
How the hidden module works
The module is wired between the supply and the load (a light, for example), and the ordinary switch is wired to its input. Pressing the switch sends the command through the module, and a command from the app switches the load directly. Both controls work together with no change to the wall.
Which module to choose
| What you want | Module | Note |
|---|---|---|
| Ordinary lighting (1–3 gang) | NEXRE-1G-Z / NEXRE-2G-Z / NEXRE-3G-Z | 16A, with power monitoring per the datasheet |
| Dimming | NEXRE-2D-Z | Two channels, 2 × 100W at 230V |
| Curtain motor | NEXRE-1C-Z / NEXRE-2C-Z | 3A per channel |
| Garage door | NEXRE-GC-Z | Open and close from the phone |
| Link another system (gate, lock) | NEXRE-DC-Z | Dry contact, COM / NO / NC |
The critical point: neutral and space
Warning
Open the switch box before buying: if there is no neutral (N) wire the module will not work, and if the box is cramped you may need to fit the module in the ceiling box. Do not use the module for large air-conditioner or heater loads.
Conversion steps
- Choose the rooms to start with (usually living room and bedroom).
- Confirm neutral and space in the boxes.
- Install the gateway in the middle of the home.
- Fit the modules (qualified electrician) with the power off.
- Add the modules to the app and build scenes.
Common mistakes
- Buying modules before checking the boxes.
- Cramming the module into a tight box, so it overheats.
- Forgetting the gateway for -Z models.
- Connecting a load above the rating.
Buy from our store
Every product in this guide is sold directly in the Fu-Mech online store. Press “Buy in store” next to a product to open its store page, or open the product page for specifications and the datasheet.
| Model | Product | Buy |
|---|---|---|
| NEXRE-1G-Z | Zigbee 1-Gang 16A Switch Module | Buy in store ↗ |
| NEXRE-2G-Z | Zigbee 2-Gang 16A Switch Module | Buy in store ↗ |
| NEXRE-3G-Z | Zigbee 3-Gang 16A Switch Module | Buy in store ↗ |
| NEXRE-2D-Z | Zigbee 2-Channel Mini Dimmer Module | Buy in store ↗ |
| NEXRE-1C-Z | Zigbee 1-Channel Curtain Module | Buy in store ↗ |
| NEXRE-2C-Z | Zigbee 2-Channel Curtain Module | Buy in store ↗ |
| NEXRE-GC-Z | Zigbee Mini Garage Door Controller | Buy in store ↗ |
| NEXRE-DC-Z | Zigbee Mini Dry Contact Module | Buy in store ↗ |
| NEXHUB-NH | Ethernet Smart Home Gateway, Zigbee 3.0 | Buy in store ↗ |
Frequently asked questions
Does the old switch still work?
Yes, it still works by hand, with phone control added.
Do I need to rewire?
Usually not, as long as there is a neutral in the box.
Who fits the modules?
A qualified electrician, with the power off at the panel.
References
- NEXSMART — NEXRE-XG-Z switch module and NEXRE-DC dry-contact datasheets
- SBC 401 — Saudi Electrical Code
Product information comes from its pages on this site and NEXSMART data; other points are general practice. Electrical connections should be made by a qualified electrician.
